Caption: Supernova explosion. 3D supercomputer simulation of a supernova expanding 9,158 seconds after ignition. The model represents a supernova measuring around 23 million kilometres in diameter. Colours represent outer surface chemical composition: blue for nickel, red for oxygen, green for carbon. Jets of stellar material are emerging from the star surface. Supernovae occur when a massive star has run out of nuclear fuel and its core collapses to form a neutron star. The collapsed core triggers a shock wave that powers the supernova explosion.